What did you guys use for covering all of the screw holes and evening out the edges prior to primer?

Wood filler? Bondo? What name to look for exactly?

What is available for me to get at Lowes/Home Depot?

I have Had the urge since I finished mine to rubberize it. If I could find an affordable option I would rhino guard it just like a truck bed. :-). I'm not sure what if anything that would do to the sound.

I certainly would not put a trap in the same corner as I am trying to load the sub into - seems like that would sort of defeat the purpose of corner loading.

When I built my THT LP, I asked that question of BFM, and he said it wasn't an issue at all, and in practice it hasn't been - my THT LP lays horizontally behind my screen wall, firing into the left wall about 18-24" away - right into a 24" SuperChunk.

I just wanna say thanks again to lilmike for this design. It has brought REAL 20Hz performance to many who cannot afford hi-spl, 20Hz, low distortion sound by conventional means (sealed/ported).....

Seeing folks' impressions when they first fire up their F20s reminds me of the first time I fired up a horn sub w/ proper EQ.....and the eye-opening that happened....."so THAT's what it's supposed to sound like!"

I just wanna say thanks again to lilmike for this design. It has brought REAL 20Hz performance to many who cannot afford hi-spl, 20Hz, low distortion sound by conventional means (sealed/ported).....

Seeing folks' impressions when they first fire up their F20s reminds me of the first time I fired up a horn sub w/ proper EQ.....and the eye-opening that happened....."so THAT's what it's supposed to sound like!"

Well, after putting in a half-hour here and an hour there for the past week I finally got it all together and running. It's just breaking in now but after running a few quick tests I can say this sub performs just as advertised. Clean, loud and low.

It was quite easy to build and I can't see how you could beat the clean spl for the money one of these costs. Very happy with the performance.

$129 driver
$149 amp
$150 all other materials.

I haven't finished the exterior although I did use pre-finished birch so it's not just sanded plywood sitting in my living room. For a few bucks more I can easily give it a flat black finish to go with the man-cave theme I have going.

Thanks Lilmike for the time you invest in this hobby, it's appreciated.

Well, after putting in a half-hour here and an hour there for the past week I finally got it all together and running. It's just breaking in now but after running a few quick tests I can say this sub performs just as advertised. Clean, loud and low.

It was quite easy to build and I can't see how you could beat the clean spl for the money one of these costs. Very happy with the performance.

$129 driver
$149 amp
$150 all other materials.

I haven't finished the exterior although I did use pre-finished birch so it's not just sanded plywood sitting in my living room. For a few bucks more I can easily give it a flat black finish to go with the man-cave theme I have going.

Thanks Lilmike for the time you invest in this hobby, it's appreciated.

Danielson, what amp did you end up getting? Nevermind, I'm assuming it was the Bash300...Get some pictures and more info when you can!

Cool, thanks. Sort of off topic, but is it important that this driver remain vertical? I know at the beginning of this thread, lilmike says the orientation remains fairly vertical...is this imperative? Also, can the horn length be "simply" lengthened to get more extension, or would it require a complete rework of the design? Thanks for any help people can provide...not that the extension is needed, but something I've sort of wondered...

It is better that the driver remain vertical, over time, cone sag can occur in a horizontal setup. which with the design isnt advisable anyways since the mouth would either be firing straight up, or into the floor.

Cool, thanks. Sort of off topic, but is it important that this driver remain vertical? I know at the beginning of this thread, lilmike says the orientation remains fairly vertical...is this imperative? Also, can the horn length be "simply" lengthened to get more extension, or would it require a complete rework of the design? Thanks for any help people can provide...not that the extension is needed, but something I've sort of wondered...

matt

Sure, more extension likely means more excursion which means more power which might mean different driver.

If you want a horn that goes lower a good model might be the one on the CSS website seen HERE

I thought about building it until I realized it won't even fit vertically into my room.

As I sit here listening to music on my system I can't help but look over at the F-20 and think to myself "WTF was I thinking!"
Needless to say it's a beast, in size and output.

Sure, more extension likely means more excursion which means more power which might mean different driver.

If you want a horn that goes lower a good model might be the one on the CSS website seen HERE

I thought about building it until I realized it won't even fit vertically into my room.

As I sit here listening to music on my system I can't help but look over at the F-20 and think to myself "WTF was I thinking!"
Needless to say it's a beast, in size and output.

corner on that still seems to be 20, maybe 18. MK will vouche as well that the f-20 is capable down to 15hz if multiples are built, perhaps even with a single. LilMike stresses a HPF at 20hz but give it a gradual rolloff, and it should play just as low as that gigantahorn

Cool, thanks. Sort of off topic, but is it important that this driver remain vertical? I know at the beginning of this thread, lilmike says the orientation remains fairly vertical...is this imperative? Also, can the horn length be "simply" lengthened to get more extension, or would it require a complete rework of the design? Thanks for any help people can provide...not that the extension is needed, but something I've sort of wondered...

matt

With a big, heavy driver, cone sag can cause issues over time. For that reason, I like to keep the coils on as close to a horizontal axis as I can.

Longer = more extension, which also means the horn gets bigger and more demands are placed on the driver. I already reworked the design as the F-24. Add 4 cubic feet. Gain ~3 Hz of extension. Lose ~3 dB of sensitivity.

Quote:

Originally Posted by Danielson99

Sure, more extension likely means more excursion which means more power which might mean different driver.

If you want a horn that goes lower a good model might be the one on the CSS website seen HERE

I thought about building it until I realized it won't even fit vertically into my room.

As I sit here listening to music on my system I can't help but look over at the F-20 and think to myself "WTF was I thinking!"
Needless to say it's a beast, in size and output.

The bulk of the plots discussing that CSS horn are not in a 2pi environment. To be fair, it is clearly stated. No doubt that it is a good horn, and it is a clever design, but comparing those plots to what I have posted is not an apples to apples comparison. There is really not much difference between the two when they are compared on a level playing field, maybe a Hz or two.

Quote:

Originally Posted by beastaudio

corner on that still seems to be 20, maybe 18. MK will vouche as well that the f-20 is capable down to 15hz if multiples are built, perhaps even with a single. LilMike stresses a HPF at 20hz but give it a gradual rolloff, and it should play just as low as that gigantahorn

I highpass because I run things hard, and also because when a bandwidth-limited sub is driven with an out of band signal, it results in distortion even if it does not make the driver go clank. I don't like asking drivers to operate outside of their intended passbands. We do the same with our midbasses (we don't ask them to be a subwoofer (well - some of us don't...) or ask them to tweet) and our tweeters (we certainly don't expect them to woof), why treat our subs any differently? It is just much more effective to handle sub crossovers actively rather than passively.

Looks like the F20 didn't fare as well as I was expecting over at Subfest2011 (if you disregard value for a moment). The comments seem to follow the line "lots of output, but muddy sound". I just finished physical construction of 2 of these (sans finish), and I'm wondering if anybody has ideas on what might have contributed to the lack of clear sound that the Subfest team observed. The subs were EQ'd fo Subfest, which would seem to reduce basic frequency response anomalies, so I'm wondering if perhaps the lack of cabinet bracing, internal sound absorption, or the raw physics of a horn design (which I won't pretend to understand yet) contribute to distortion in the time domain that could be corrected. I have noticed that the cabinets are not "dead" sounding when I knock on them.
Thoughts?